Tamper-evident cap and neck finish

Abstract

A neck finish for a tamper evident bottle is disclosed having at least ten helically spaced threads which extend along a substantial length of the exterior wall of the neck. The neck finish may include one or two annular ring flanges to accept a snap-on cap. Also disclosed are tamper evident caps having at least ten helically spaced threads positioned on the inner surface of the cap. In one embodiment, the cap includes one or two annular ring flanges to engage the ring flanges on the disclosed neck finish. Another tamper evident cap includes ten helically spaced thread which are adapted to engage at least some portion of threads on a neck finish.

What is claimed is: 
     
       1. A neck finish for a container comprising: a. an annular wall with an outer surface and an inner surface defining a cylindrical opening therethrough, said annular wall having a first and second end, said first end being open to provide access to said cylindrical opening and having an annular flange extending from said inner surface of said annular wall into said opening in said first end;   b. at least one set of ratchet teeth positioned around a portion of said outer surface of said annular wall at said second end;   c. at least ten threads angularly positioned on said annular wall between said first end and said ratchet teeth each of said treads extending around said surface less than 90° and wherein said threads are discotinuous at a mold parting line; and   d. a first annular ring flange on and extending substantially around said outer surface of said annular wall adjacent to said set of ratchet teeth, said first annular ring flange adopted to engage an associated ring flange on a cap to sealing position said cap onto said neck.   
     
     
       2. A neck finish for a container as set forth in claim 1 including a second annular ring flange positioned on said outer surface of said annular wall between said first end and said threads. 
     
     
       3. A neck finish for a container as set forth in claim 1 or 2 wherein said annular ring flanges includes a circumferential lip. 
     
     
       4. A tamper-evident cap in combination with the neck finish of claim 1, said tamper-evident cap comprising: a. a closure member having a cover with a substantially circular periphery, said closure member having an annular wall depending from said periphery and including an internal surface;   b. a removable tamper-evident band circumferentially positioned around said depending annular wall opposite from said cover, said tamper-evident band including at least one internal neck finish engagement means;   c. a first annular ring flange position around said internal surface of said depending annular wall adjacent said tamper-evident band adopted to engage said first annular ring flange of said neck to sealing position said cap on said neck finish;   d. an annular valve depending from said cover and spaced apart from said internal surface of said annular depending wall a distance sufficient to sealingly engage said annular flange of said neck finish; and   e. at least ten threads spaced apart and helically positioned on said internal surface of said annular depending wall extending from about said first annular ring flange to proximate said closure member each of said threads extending less than 180°.   
     
     
       5. A tamper evident cap as set forth in claim 4 made from high density polyethylene. 
     
     
       6. A tamper evident cap as set forth in claim 4 made from low density polyethylene. 
     
     
       7. A tamper-evident cap as set forth in claim 4 including a second annular ring flange positioned between said cover of said closure member and said helical threads. 
     
     
       8. A tamper-evident cap as set forth in claim 4 or 7 wherein said annular ring flanges includes a circumferential lip. 
     
     
       9. A tamper evident cap as set forth in claim 4 or 7 wherein said helical threads extend less than 270° around said internal surface. 
     
     
       10. A tamper-evident cap as set forth in claim 4 or 7 wherein said threads each extend around said internal surface less than 90°. 
     
     
       11. A neck finish for a container and a tamper-evident cap for the neck finish comprising: a. an annular wall on the neck finish defining a cylindrical opening therethrough into the container at a first end and having an external surface;   b. at least one set of ratchet teeth positioned around a portion of said external surface of said annular wall at a second end;   c. a first annular flange ring on said external surface between said cylindrical opening and said ratchet teeth;   d. at least ten threads helically positioned on said external surface between said first end and said ratchet teeth and extending less than 180° and being discontinuous at a mold part line;   e. said cap having a closure on a first end annular wall for closing said cylindrical opening in the neck finish, said closure having a depending annular wall around the periphery of said closure, said depending annular wall having an internal surface;   f. a tamper-evident band circumferentially positioned around a second end of said depending annular wall of the cap and having at least one set of ratchet teeth for engaging said ratchet teeth on the neck finish;   g. a first annular ring flange positioned around said internal surface of said depending annular wall for engaging said first annular ring flange on the neck finish; and   h. at least ten threads spaced apart and helically positioned on said first annular ring flange and said closure, said threads on the cap being equal in number and helical angle to said at least ten threads on the neck finish.   
     
     
       12. A neck finish for a container as set forth in claim 1 or 11, wherein said annular wall includes a pair of molding part lines and said helical threads are discontinuous at said part lines. 
     
     
       13. A tamper-evident cap comprising: a. a closure member at a first end with a depending annular wall around the periphery of said closure member, said annular wall having an internal surface;   b. a tamper-evident band circumferentially positioned around a second end of said depending annular wall;   c. a first annular ring flange positioned around said internal surface of said depending annular wall; and   d. at least ten threads spaced apart and helically positioned on said internal surface of said annular depending wall between said first annular ring flange and said closure member and each of said threads extending less than 90° around said surface and having a lead-in adjacent said first annular ring flange to permit snapping on said cap to a neck finish.   
     
     
       14. A tamper-evident cap as set forth in claim 13 including a second annular ring flange, said first annular ring flange positioned between said tamper-evident band and said helical threads, and said second annular ting flange positioned between said closure member and said helical threads. 
     
     
       15. A neck finish and tamper-evident cap as set forth in claim 14, including second annular ring flanges positioned on the neck finish and cap, respectively, in interengaging relationship. 
     
     
       16. A neck finish and tamper-evident cap as set forth in claim 14, including breakable means on said annular depending wall of the cap between said threads and said second annular ring flange for breaking upon removal of the cap from the container.